Project Management and Critical Path Analysis in Construction

School: Concordia University - Course: COMM 225 - Subject: Accounting

3 Activity/Work PackagesDuration (in months)Immediate Predecessor A. Project Approval3- B. Decide general requirements6A C. Choose A/E firm2A D. Preliminary Design3B,C E. Choose Project Management firm2B F. Decide detailed requirements6D,E G. Finalize design6F H. Schedule, budget, manual4F I. Start bid packages2G,H J. Excavate, foundation, steel structure10I K. Put up enclosures7J PCT = 57 months SL= 1 SL= 0 SL = 0 Problem17-18 36K43 36743 18G 24 18624 9E1110212 3B9 369 SL = 0 55O57 55257 43N55 431255 36L423764326J3626103624I262422612F18 12618 9D1293120A3 033 Slack = Late Start - Early Start = Late Finish - Early Finish SL = 0 SL = 0SL =0 SL =4 SL = 0SL = 0 SL = 2 SL=0 SL = 0SL =136M41 38543 18H22 20424 3C5 729 SL = 2 Critical Path: Activities with zero slack make up the critical path: A-B-D-F-G-I-J-K-N-O Forward Pass Computations: With forward pass computations we determine the early schedule for the project and the Project Completion Time (PCT). When an activity has 2 or more preceding activities, then we take the greater EF time of predecessors to set the ES time of that activity. Convention: ES = Early Start time of an activity; EF = Early Finish time of an activity ; PCT = Project Completion Time LS = Late Start time of an activity; LF = Late Finish time of a activity; D = activity duration SL = slack time of an activity= forhow long an activity can be delayed without delaying the project completion time.Backward pass computations are used to identify the late schedule and slack for each activity and the critical path. When an activity has more than two successors, we take the smaller late start time of successorsto determine the late finish time of that activity.

L. HVAC,fire protection, plumbing6J M. Electrical5J N. Interior finishes12K,L,M O. Close out project2N Problem 17-18: Consider the construction of a research building for Eli Lilly & Co., a pharmaceutical company, a few years ago. This 550,000 ft2. 4-story (in 3 wings), $135 million building was planned to be completed in five years. It required special ventilation for 162 labs, purified water, and special drainage. Consider the following list of major activities/work packages (as seen by Eli Lilly), their expected duration, and their relationship to other activities/work packages for the Eli Lilly building. (a) Draw the precedence network. (b) Determine the ES, EF, LF, and LS times. (c) What is the project duration? (d) What are the critical activities? O (2) N (12 )) M (5)L (6) K (7) J (10 )I(2)H (4) G (6 )) F (6) E (2) D (3) C (2)B (6) A(3)

Example:Setting up an office space Project Completion Time = 20 weeks Critical Path = S-1-5-7 Slack = by how many weeks each activity can be delayed without delaying the project completion time. Paths: DurationSlack S-1-2-6-718 weeks20-18 = 2weeks S-1-5-720 weeks20-20=0 14 weeks20-14 = 6 weeks